LC-MS/MS Quantitation & Clinical Applications

Connect small-molecule quantitation, isotope-labeled standards, TDM and immunoassay comparisons into a clinical-MS method strategy.

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Mass Spectrometry & Applications2026/6/24

Why Is Mass Spectrometry the Gold Standard for Small-Molecule Analysis?

LC-MS/MS has become the gold standard for small-molecule analysis. Its core advantages include: achieving highly precise quantification based on stable isotope-labeled internal standards, simultaneously detecting dozens of analytes in a single analysis, and accurately distinguishing compounds with highly similar structures.

LC-MS/MSStable Isotope Internal StandardsClinical Mass SpectrometryQuantitative Analysis

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Mass Spectrometry & Applications2026/6/24

Selection of Stable Isotope Internal Standards: Why Are 13C/15N-Labeled Standards Usually Superior to Deuterated Internal Standards?

13C- and 15N-labeled internal standards generally offer better chromatographic consistency and long-term stability, whereas deuterated internal standards have a clear cost advantage. This article introduces the advantages, disadvantages, and application scenarios of different stable isotope labeling strategies.

Internal StandardsLC-MS/MSIDMS

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Mass Spectrometry & Applications2026/6/24

Design Principles for Delta MS Between Isotopic Internal Standards and Target Molecules

The rational design of Delta MS requires integrating molecular weight, natural isotope distribution, and elemental composition. For large molecules containing two chlorine atoms, such as vancomycin, Vancomycin-D10 can provide a sufficient mass difference for reliable internal standard correction in LC-MS/MS quantification.

Delta MSDelta MassStable Isotope Internal StandardsLC-MS/MS

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Mass Spectrometry & Applications2026/6/24

Vancomycin Testing: Comparison of LC-MS/MS and Immunoassays

The therapeutic concentration of vancomycin is close to its toxic concentration, making precise therapeutic drug monitoring essential for individualized dosing. This article compares the characteristics of immunoassays and LC-MS/MS methods in vancomycin testing and explains the central role of stable isotope-labeled internal standards in high-quality quantitative mass spectrometry.

Therapeutic Drug MonitoringLC-MS/MSClinical Mass SpectrometryStable Isotope Internal Standards

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Mass Spectrometry & Applications2026/6/24

Why Do Clinical Laboratories Mainly Use Immunoassays for Macromolecule Testing, While Increasingly Using Mass Spectrometry for Small-Molecule Testing?

In clinical laboratories, macromolecule testing has long been dominated by immunoassays, whereas small-molecule testing is increasingly shifting toward LC-MS/MS. The division of roles between the two types of technologies stems from differences in the analytes themselves: proteins and peptides have multiple epitopes and are well suited to dual-antibody sandwich recognition; small molecules are compact and have many structural analogs, making competitive immunoassays more susceptible to cross-reactivity, and therefore better suited to mass spectrometry platforms that rely on recognition of molecular structural features.

Clinical Mass SpectrometryImmunoassayLC-MS/MSStable Isotope Internal Standards

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